1. Field of the Invention
This invention relates to a cut off apparatus, and in particular to an automatic self-adjustable cut off apparatus for cutting bumper-length segments from an elongated article having varying degrees of curvature, or sweep, made on a continuous roll-forming and sweeping process.
2. Description of Related Art
In the prior art, cut off apparatuses are used in-line with roll forming machines to cut lengths of roll-formed articles. Also commonly used in-line with roll forming machines are sweep-forming apparatuses which introduce a longitudinal curvature, or sweep, into the roll-formed elongated article. Standard cut off devices are not particularly well suited to sever such elongated swept articles. Traditionally, this problem was attempted to be solved by use of a track to guide the cutoff mechanism during the cutting stroke. More recently, a cut off apparatus is described in U.S. Pat. No. 5,305,625 that automatically adjusts to variations in speed and minor changes in curvature to cut bumper-length segments from an elongated swept article.
Unfortunately, the prior art does not address the long standing need for an automatic means to cut elongated articles which have varying degrees of curvature, or compound sweeps. Articles such as motor vehicle bumpers are manufactured on a roll-forming machine and are then curved along the longitudinal direction on a sweep-forming apparatus. The sweep-forming apparatus initially introduces in to the article a curve of a smaller radius, followed by a curve of a larger radius, and finally another smaller radius curve. This permits a single bumper element to match the contour of the front or rear of a motor vehicle, and overlap slightly around the sides of the vehicle.
The varying radii of such articles prevent the use of cut off devices designed for elongated articles swept with a constant curve. This problem arises because the portion of the compound swept elongated article that passes through the cut off apparatus moves relative to the cutting device, both with respect to the height of the article and with respect to the relative angle between the cutting means and the article. Currently, this problem is overcome by pausing the manufacturing process and manually severing the elongated compound swept article. Problems with this solution, however, include increasing the time necessary to manufacture bumper elements, and difficulty in ensuring that the article is perpendicularly severed at a precise length.
Accordingly, it is desirable to provide an automatic cut off apparatus that automatically adjusts for elongated articles having compound sweeps and perpendicularly severs the article at predetermined lengths.
To meet the above described desires, the present self-adjusting cut off apparatus for automatically cutting segments of a predetermined length from an elongated compound swept article is disclosed. In a preferred embodiment the present invention provides an apparatus having a frame with a fixed base, a pair of support columns fixedly mounted on the base, an overhead support fixedly mounted on the support columns, and a pair of support braces fixedly mounted on both the support columns and the base. A carriage is movably mounted on the support columns for ascending and descending the apparatus. A first arm is pivotally mounted on the carriage. A second arm is pivotally mounted on the distal end of the first arm. A cutter housing is pivotally mounted on a mounting plate which is perpendicularly fixed to the distal end of the second arm. The cutter housing includes a first passageway and a second passageway through which the elongated compound swept article enters and exits, respectively, rollers for supporting the article in the cutter housing, and an automatic cutting means. The carriage, first arm, second arm, and cutter housing are supported by a counterbalancing means which allows the carriage, first arm, second arm, and cutter housing to operably move in a substantially xe2x80x9cweight freexe2x80x9d state. The combined length of the first arm and the second arm equals the radius of the larger curves in the elongated compound swept article, and the length of the second arm equals the radius of the smaller curves in the article. During the operation of the apparatus, the cutter housing receives the elongated compound swept article. As the larger radius curved portions of the elongated article pass through the cutter housing, the first arm pivots in the direction of the moving article, carrying the second arm and cutter housing along with it. When the smaller radius curved portions of the elongated article pass through the cutter housing, the first arm remains still and the second arm pivots in the direction of the moving article, carrying the cutter housing along with it. Through the carriage and counterbalance, the cutter housing adjusts for the varying height of the elongated compound swept article. The cutting means is positioned within the cutter housing at a point co-linear with the longitudinal axes of the first arm and second arm such that during the cutting stroke the elongated compound swept article is perpendicularly severed.
It is a feature of the present invention to provide a cut off apparatus that automatically adjusts for changes in the degree of curvature and height in an elongated compound swept article.
It is another feature of the present invention to provide a cut off apparatus that automatically operates in line with a roll-forming machine and a sweep-forming apparatus as they continuously produce elongated compound swept articles.
It is a further feature of the present invention to provide a cut off apparatus that can perpendicularly cut predetermined lengths from an elongated compound swept article.
The above noted and other features of the present invention will become more apparent to those skilled in the art as the invention is further explained in the accompanying drawings and detailed description.